Bending wood



SATES AT T FIC.

THOMAS BLANCHARD, OF BOSTON, MASSACHUSETTS.

BENDING WOOD.

Specification forming part of Letters Patent No. 6,951, dated December 18, 1849; Ressued November 15, 1859, No. 853.

To all whom 25 may concern Be it known that I, THOMAS BLANCHARD, of the city of Boston, in the county of Suffolk and State of Massachusetts, have invented a new and useful Improvement, being a Method of Bending Timber and other Fibrous Substances; and I do hereby declare that the following specification and drawing making part of the same is a full description ofI my new Inode or method of accomplishing the said object, which I have exemplified in one form of machinery for bending plow-handles. Other articles will require different forms and different arrangements of machinery.

Figure l is a top view of the machine, with the mold lever brought home to its place after the operation of bending is completed. Fig. 2 is a top view with the mold lever thrown open to receive the timber for the operation. Fig. 3 is a sectional side .View of the sliding beam E and` bench A.

Fig. 4 is a transverse section and end view of Fig. l. Fig. 5 is another transverse end View section of Fig..l.

The same letters apply to all the figures.

A A is the bed piece or bench on which the machine is formed and may be made of wood or metal.

B is the mold that gives the curve to the inside of t-he handle turning on a pin or fulcrum O the other end extending back of suiiicient length to form a lever of sufficient power to bend the handle when brought around one quarter of a circle more or less as is required.

D is the chain with hollow links that forms the outside of the handle and extends the whole length of the curve part of the handle and is connected at one end to a sliding bar J on one side of the mold lever B. The other end of the said chain is con` nected by two straps E parallel with each other, (only one of them is shown in the drawing) the whole length of the handle and made fast to the sliding beam E by a joint at R and of suiiicient distance apart for the handle G to lay between them, each strap is connected by a pin to the last link of the chain, one on each side of said link.

AH, is the upsetting screw passing through from the one before mentioned. This screw` serves to grip the top end of the handle and hold it fast between the first link of the chain and the mold D and allows various sizes of handles to enter the same mold and is brought to its bearing before the bending of the handle commences.

K is a set screw passing through a stationary fiange on one side of the bench, and serves to press one end of the sliding beam E against the back, or outside of the chain at the bending point, and keeps the chain and sliding beam at a suiicient distance from the mold lever sufficient to allow the timber, or handle to lay between them.

O is a clamp made fast to the top of the flange by two screws, one end o-f which is a hook, falling into a groove on the top of the sliding beam and serves to keep thatl end of the sliding beam in its place, but allows it to slide freely.

C is the fulcrum or pin in which the mold lever turns, this pin is supported on top of the lever by a bra-ce M, through which it passes into the bench, the other end of said brace extends across the bench over the sliding beam and is made fast to the stationary flange a part of the bench.'

L is a key or wedge to hold the timber firm in its bed in the sliding beam and prevents its springing sideways while the upsetting and bending process is performed.

N is a spring catch niade fast at one end to the bench, the other endA having a hook to hold the mold lever when the operation of bending is performed as shown in Fig. l.

The mode of operation is as follows: The mold lever is thrown open at right angles with the bench as shown in Fig. 2, the timber or handle G is placed in the round end extending forward between the chain and the mold, the other end extending back to the upsetting screw the key L, is then driven the upsetting screw H, and turns it forward y and presses the 'handle endwise, driving the upper end firm against the slide J, which is connected with the first link "of thechain which operation strengthens the chain taut and completes the preparation ready for the bending process, power is then applied to the end of the mold lever and brought around which draws the sliding beam forward with the handle as the curve is formed, the upsetting screw follows with the handle and sliding beam, and prevents the outside of the vtimber at the curve from parting or breaking during the operation the upsetting screw should be relaxed a little, to prevent the timber on the inside of the curve from crippling or overlapping when the mold lever is brought home to its place the spring catch takes hold of the end of the lever and prevents it from going back, and the work is completed. a

That part of the pawl handle which is bent is of an oval form and is turned or wrought in proper shape before it is bent, it is formed deepest or thickest transversely to the curve, consequently the links or blocks that forms the chain are hollow to conform to the outside ofthe curve, and the lever mold having a corresponding'hollow to t the inside.

The chain may be dispensed with in bending large curves with flat sides, such as felloes for wheels where the sides having flat surfaces. A metallic strap of metal may be substituted,- and a number of pieces can be put to the operation of bending at once in the same mold or a whole plank of suitable thicknesses may be-bent at once, and sawed into felloes afterwards, in that case, there would be no side twist or winding in the operation of bending, but if they are sawed into squares before bent, the wind or side crook may be prevented by placing a number together, and prevent the side spring by side clamps to keep them in the right direction while they are bent, these side clamps may extend around the mold which will prevent the side movement while receiving the proper curve.

A cylinder or drum may be used for a mold formed cylindrical, or elliptical or any figure requiredand instead of a lever to move it, cog wheels may be used and any termi ne.

I power applied. The upsetting power must be given by the screw or other mechanical power when the timber is first placed in the mold while in its straight form, by screwing or pressing against the ends of the timber-care should be taken to prevent its crippling by having clamps attached to the sliding bed. As soon as the bending process commences, the end pressure, or upsetting screw must begin to relax inrproportion to the thickness ofthe timber, and shortness of the arc of the curve requiredalso in proportion to the toughness, or tenderness of the timber, but no definite rule can be given. Experience only can de.- In all cases the end pressure must be kept sufficiently tight, so as to prevent the outside of the curve from parting or breaking while the inside of the curve the timber will be upset-this relaxation of the end pressure must be continued until the Work is done. There are many mechanical methods by which the relaxation of the end pressure can be made self actingand uniform-one of which, is as follows-on the end of the upsetting screw H a bevel tooth wheel meshing into another bevel wheel may be attached at one end of a shaft at right angles with the upsetting screw-on the other end of the shaft may be attached a spur wheel meshing into a. stationary'rack; as the sliding bed advances in the operation lof bending t-he spur wheel meshing into the stationary rack will turn the bevel gears and the upsetting screw H, in a backward direction, thus relaxingthe pressure against the end of the timber uniformly during the whole operationto vary the speed of the relaxing screw, for the various curves and thicknesses of timber to be bent, a number of spur wheels of different sizes may be placed on the shaft so that either of them can mesh into the rack at pleasure, which will vary the speed as required on the outside of the bevel wheel on the upsetting screw-instead of a thumb piece for it, as shown in the drawing a cra-nk may be substituted, which would be preferable in heavy work to throw the screw forward with suicient powerthe bevel wheel on the screw shaft H may be connected with it by a ratchet wheel and pawl so that the screw can be driven forward when the timber is first placed in the sliding bed by turning the crank without revolving the gear work, and when it is reversed by the gear, the pawl will take hold the ratchet wheel which is made fast to the screw shaft.

I do not claim as my invention the mechanical powers by which the operation of bending timber is eifected-nor any particular form of machinery to carry my new method into operationbut the machine herein described is a form which I have adopted to carry out, and Combine-my new produced by means of the screw, Wedge, method of bending timber. But comb, lever, rack and pinions, or any other 10 vWhat I do claim isequivalent means. My method of bendinov fibrous materials 5 by means of the upsetting movements or the THOS' BLANCHARD' upsetting and relaxing movements com- Witnesses: bined, as exemplied in the screw H, EDWARD F. HALL, Whether such movement, or movements, be DUDLEY H. BAYLEY.

[FIRST PRINTED 1913.] L 

